Non-contact voltage measurement device and diagnosis system

Abstract

Provided are a non-contact voltage measurement device and diagnosis system capable of acquiring the voltage of an electric wire without disconnecting the wire. The non-contact voltage measurement device (100) includes: a cylindrical fixing part (110) for holding an electric wire (10) by clipping the same from both sides; a first electrode (121) and a second electrode (122) provided on the inner peripheral surface of the electric-wire-holding side of the fixing part (110) so as to be separated by a distance (D2); a first measurement capacitor (C3) and a voltage division capacitor (C2) connected to the first electrode (121); a second measurement capacitor (C3′) connected to the second electrode (122); a terminal (131) for measuring the voltage (V1) applied to the first measurement capacitor (C3); and a terminal (132) for measuring the voltage (V2) applied to the second measurement capacitor (C3′).

The invention claimed is: 
     
       1. A non-contact voltage measurement device used for measuring a voltage applied to a core wire of an electric wire which is coated with an insulator, without contacting the core wire,
 the device comprising:
 a fixing part arranged to hold the electric wire; 
 a first electrode and a second electrode that are provided in the fixing part separately from each other; 
 a first measurement capacitor and a first voltage division capacitor that are connected to the first electrode; 
 a second measurement capacitor that is connected to the second electrode; and 
 a voltage measurement detector configured to measure a voltage applied to the first measurement capacitor and a voltage applied to the second measurement capacitor, 
 wherein the fixing part holds the electric wire in such a manner that a force of pressing the first electrode against the electric wire and a force of pressing the second electrode against the electric wire are equal to each other, 
 wherein an area over which the first electrode is in contact with the electric wire and an area over which the second electrode is in contact with the electric wire are made equal to each other, and 
 wherein the fixing part is cylindrical and holds the electric wire with an inner peripheral surface, the first and second electrodes axially separated from each other along the cylinder. 
 
 
     
     
       2. A non-contact voltage measurement device used for measuring a voltage applied to a core wire of an electric wire which is coated with an insulator, without contacting the core wire,
 the device comprising:
 a fixing part arranged to hold the electric wire; 
 a first electrode and a second electrode that are provided in the fixing part separately from each other; 
 a first measurement capacitor and a first voltage division capacitor that are connected to the first electrode; 
 a second measurement capacitor and a second voltage division capacitor that are connected to the second electrode; and 
 a voltage measurement detector configured to measure a voltage applied to the first measurement capacitor and a voltage applied to the second measurement capacitor, 
 wherein the fixing part holds the electric wire in such a manner that a force of pressing the first electrode against the electric wire and a force of pressing the second electrode against the electric wire are equal to each other, 
 wherein an area over which the first electrode is in contact with the electric wire and an area over which the second electrode is in contact with the electric wire are made equal to each other, and 
 wherein the fixing part is cylindrical and holds the electric wire with an inner peripheral surface, the first and second electrodes axially separated from each other along the cylinder. 
 
 
     
     
       3. The non-contact voltage measurement device according to  claim 1 , further comprising:
 a circuit configured to arithmetically operate a voltage applied to the core wire of the electric wire, on the basis of a capacitance of the first measurement capacitor and a capacitance of the first voltage division capacitor, and the measured voltages. 
 
     
     
       4. The non-contact voltage measurement device according to  claim 3 ,
 wherein the circuit is configured to arithmetically operate a voltage applied to the core wire of the electric wire in accordance with the following formula:
   Voltage=(first measurement capacitor/first voltage division capacitor)*(voltage 1*voltage 2)/(voltage 1−voltage 2),
 
 
 where the first measurement capacitor is a capacitance of the first measurement capacitor, first voltage division capacitor is a capacitance of the first voltage division capacitor, voltage  1  is the voltage applied to the first measurement capacitor, and voltage  2  is the voltage applied to the second measurement capacitor. 
 
     
     
       5. The non-contact voltage measurement device according to  claim 2 , further comprising:
 a circuit configured to arithmetically operate a voltage E applied to the core wire of the electric wire, on the basis of a capacitance of the first measurement capacitor, a capacitance of the first voltage division capacitor, the second measurement capacitor, the second voltage division capacitor, and the measured voltages. 
 
     
     
       6. The non-contact measurement device according to  claim 1 , wherein a separation distance between the first electrode and the second electrode is larger than a radial distance from an outer peripheral portion of the core wire of the electric wire to the first electrode or the second electrode. 
     
     
       7. The non-contact voltage measurement device according to  claim 1 , wherein the first electrode is provided on an inner peripheral surface of one cylindrical end of the fixing part and the second electrode is provided on an inner peripheral surface of the other cylindrical end of the fixing part. 
     
     
       8. The non-contact voltage measurement device according to  claim 1 , wherein the fixing part is provided with a grip and hold section which grips and holds the electric wire. 
     
     
       9. The non-contact voltage measurement device according to  claim 1 , wherein the fixing part is provided with an adjuster configured to adjust a force of pressing the first electrode against the electric wire and a force of pressing the second electrode against the electric wire. 
     
     
       10. A diagnosis system used for diagnosing a state of equipment including a rotating machine by using a voltage which is measured by the non-contact voltage measurement device according to  claim 1 . 
     
     
       11. The non-contact measurement device according to  claim 2 , wherein a separation distance between the first electrode and the second electrode is larger than a radial distance from an outer peripheral portion of the core wire of the electric wire to the first electrode or the second electrode. 
     
     
       12. The non-contact voltage measurement device according to  claim 2 , wherein the fixing part is provided with a grip and hold section which grips and holds the electric wire. 
     
     
       13. The non-contact voltage measurement device according to  claim 2 , wherein the fixing part is provided with an adjuster configured to adjust a force of pressing the first electrode against the electric wire and a force of pressing the second electrode against the electric wire. 
     
     
       14. A diagnosis system used for diagnosing a state of equipment including a rotating machine by using a voltage which is measured by the non-contact voltage measurement device according to  claim 2 .